In the search for hydrocarbons, the determination of the physical properties of the reservoir fluids is required to make the decisions concerning the economic value and reservoir management. Traditionally, samples have been taken in the field at either bottom hole, the separator or at the stock tank. These samples were then shipped to a laboratory where the fluid was reconstituted to reservoir conditions and then a number of properties measured. The properties of greatest interest immediately after a sample is taken are saturation pressure, viscosity, relative volume, compressibility at reservoir temperature and finally, composition of the sample.
Currently, the quality of the results is a measure of the care, dedication and attention to minute detail of expensive laboratory staff. The test results are subject to the limits imposed by staff endurance and attention span. Some samples require extremes in pressure, temperature and quite often, both at the same time. In addition, some samples contain materials which are toxic, such as hydrogen sulfide. Toxic samples typically require measurement procedures which are time consuming, cumbersome and often degrade the measurement quality of the sample. The time between the acquisition of a sample and the completion of a laboratory program has traditionally varied from weeks to nearly a year. The current petroleum exploration and operation environments require a subset of the physical property data at increasingly earlier time frames. Field locations are accommodation and space limited. While small laboratories can and have been placed on drilling rigs, proper staffing, safety and bed space has always been contentious.